@article {47635, title = {Achiral and chiral NNN-pincer nickel complexes with oxazolinyl backbones: application in transfer hydrogenation of ketones}, journal = {New Journal of Chemistry}, volume = {45}, year = {2021}, month = {JUL}, pages = {11927-11936}, type = {Article}, abstract = {We describe the synthesis of new NNN-oxazolinyl-pincer nickel complexes and their application in the transfer hydrogenation of ketones. Achiral NNN-ligands, R {\textquoteleft}(2)-oxazolinyl-2-C6H4-NH-C(O)CH2NEt2 [((R {\textquoteleft} 2-OxNNNEt2))-H; R{\textquoteright} = H (3a), R {\textquoteleft} = Me (3b)], and chiral ligands, (R)-R {\textquoteleft}-oxazolinyl-2-C6H4-NH-C(O)CH2NEt2 [(R)-((R {\textquoteleft}-OxNNNEt2))-H; R {\textquoteleft} = Ph (3c), R {\textquoteleft} = CH2Ph (3d), R {\textquoteleft} = Pr-i (3e), R {\textquoteleft} = (CH2Pr)-Pr-i (3f)], were efficiently synthesized. Treatment of these ligands with (DME)NiCl2 afforded the desired amido-pincer nickel complexes, ((R {\textquoteleft} 2-OxNNNEt2))NiCl [R {\textquoteleft} = H (4a), R {\textquoteleft} = Me (4b)] and ((R {\textquoteleft}-OxNNNEt2))NiCl [R {\textquoteleft} = Ph (4c), R {\textquoteleft} = CH2Ph (4d), R {\textquoteleft} = Pr-i (4e), R {\textquoteleft} = (CH2Pr)-Pr-i (4f)], in good yields. All the ligand precursors and nickel complexes were thoroughly characterized by various analytical techniques. The molecular structures of 4a, 4d and 4f were established by X-ray crystallography. The developed nickel complexes were found to be efficient catalysts for the transfer hydrogenation of ketones using (PrOH)-Pr-i as a viable hydrogen source. Enantioselectivity in hydrogenation was not observed with the developed chiral catalysts.}, issn = {1144-0546}, doi = {10.1039/d1nj01698a}, author = {Jagtap, Rahul A. and Ankade, Shidheshwar B. and Gonnade, Rajesh G. and Punji, Benudhar} } @article {47042, title = {Advances in C(sp(2))-H/C(sp(2))-H oxidative coupling of (Hetero)arenes using 3d transition metal catalysts}, journal = {Advanced Synthesis \& Catalysis}, volume = {363}, year = {2021}, month = {APR}, pages = {1998-2022}, type = {Review}, abstract = {

C-H/C-H oxidative coupling has emerged as a straightforward and powerful technique for the construction of (hetero)biaryls, with substantial application to drug discovery, agrochemicals, biology, and material sciences. Mainly aryl-aryl, aryl-heteroaryl, and heteroaryl-heteroaryl couplings via double C(sp(2))-H activation using 4d or 5d noble transition metal catalysts have been extensively studied. Considering the earth-abundant and inexpensive nature of 3d transition metals, the sustainable development of C(sp(2))-H/C(sp(2))-H oxidative coupling employing such metal catalysts has gained significant attention. In this review, we present a comprehensive overview of C(sp(2))-H/C(sp(2))-H oxidative coupling of (hetero)arenes catalyzed by 3d transition metals.

}, keywords = {(hetero)biaryls, 3d transition metal, Biaryls, C-H activation, cross-dehydrogenative coupling}, issn = {1615-4150}, doi = {10.1002/adsc.202001498, Early Access Date = MAR 2021}, author = {Bansal, Sadhna and Shabade, Anand B. and Punji, Benudhar} } @article {47398, title = {Advances in transition-metal-catalyzed C-H bond oxygenation of amides}, journal = {Synthesis-Stuttgart}, year = {2021}, month = {APR }, type = {Article; Early Access}, abstract = {

C-O bond formation represents a fundamental chemical transformation in organic synthesis to develop valuably oxygenated (hetero)arenes. Particularly, the direct and regioselective C-H bond oxygenation of privileged amides, using a transition metal catalyst and a mild oxygenating source, is a step-economy and attractive approach. During the last decade, considerable progress has been realized in the direct C-H oxygenation of primary, secondary, and tertiary amides. This Short Review compiles the advances in transition-metal-catalyzed oxygenation of C(sp(2))-H and C(sp(3))-H bonds on various amides with diverse oxygenation sources. The review is categorized into two different major sections: (i) C(sp(2))-H oxygenation and (ii) C(sp(3))-H oxygenation. Each section is discussed based on the directing group (monodentate and bidentate) attached to the amide derivatives.

}, keywords = {Amides, C-H activation, directing group, Oxygenation, Transition Metal}, issn = {0039-7881}, doi = {10.1055/a-1481-2584, Early Access Date = APR 2021}, author = {Vijaykumar, Muniyappa and Punji, Benudhar} } @article {49125, title = {Advances in the iron-catalyzed direct functionalizations of heterocycles}, journal = {Synlett}, volume = {34}, year = {2023}, month = {APR}, pages = {683-697}, type = {Article}, abstract = {

Direct functionalization of heterocycles is an advanced strategy for diversifying privileged and biorelevant heterocycle-containing molecules. Particularly, use of the most abundant transition metal, iron, as a catalyst makes this process highly cost-effective and sustainable. Recently, some progress has been realized towards the direct functionalization of heterocycles under iron catalysis. Herein, we present the developments in the C-H bond functionalizations and related reactions of various heterocycles by abundant iron salts. This Synpacts is categorized into different sections based on heterocycles being functionalized, and each section is discussed based on the type of reaction catalyzed by iron. 1 Introduction 2 Functionalization of Indoles 2.1 Alkylation 2.2 Alkenylation 2.3 Other Reactions 3 Oxindoles and isatins 3.1 C-C Bond Formation 3.2 C-Heteroatom Bond Formation 4 Pyridines and Furans 5 Functionalization of Azoles 6 Summary and Outlook

}, keywords = {Alkylation, azoles, C-H functionalization, heterocycles, indoles, iron, Mechanism}, issn = {0936-5214}, doi = {10.1055/a-1890-8503}, author = {Pradhan, Chandini and Punji, Benudhar} } @article {49020, title = {Advancement in the C-H bond alkylation of (hetero)arenes catalyzed by the most abundant transition metal-iron}, journal = {Organic Chemistry Frontiers }, volume = {11}, year = {2024}, month = {APR }, pages = {2397-2417}, type = {Review}, abstract = {

Alkylation reaction stands as a crucial organic transformation, fostering privileged alkylated arenes and heteroarenes in molecular science. Over the past decade, the utilization of the most abundant transition metal iron for regioselective C-H bond alkylation has gained substantial prominence, offering a straightforward and sustainable approach. Noteworthy progress has been achieved in the alkylation of diverse arenes and heteroarenes involving primary, secondary, and tertiary alkyl (pseudo)halide, alkene, and alcohol coupling partners via both the mono- and bidentate-chelate strategies. This concise and focused review provides an overview of the advancement in the iron-catalyzed alkylation of arenes and heteroarenes through step-economical C-H functionalization, their novel features, proposed mechanisms, and future research directions. The review is categorized into two major sections: (i) alkylation of arenes and (ii) alkylation of heteroarenes. Each section is discussed based on the class of arenes and heteroarenes used. Advancement in the direct C-H bond alkylation of arenes and heteroarenes using the catalysts based on the most abundant transition metal, iron, is summarized.

}, issn = {2052-4129}, doi = {10.1039/d4qo00063c}, author = {Pradhan, Chandini and Punji, Benudhar} } @article {49490, title = {Atroposelective construction of biaryls enabled by a Ni(II)-catalyzed aerobic oxidation strategy}, journal = {ACS Central Science}, volume = {11}, year = {2025}, month = {FEB}, pages = {187-189}, type = {News Item}, abstract = {

Enantioriched biaryls synthesis via aerobic oxidative cross-coupling of arenes involving\ bioinspired oxygen activation by Ni(II).

}, issn = {2374-7943}, doi = {10.1021/acscentsci.5c00169}, author = {Pradhan, Chandini and Punji, Benudhar} }